To date,there is still a lack of a comprehensive explanation for caged dynamics which is regarded as one of the intricate dynamic behaviors in amorphous alloys.This study focuses on Pd_(82)Si_(18)as the research objec...To date,there is still a lack of a comprehensive explanation for caged dynamics which is regarded as one of the intricate dynamic behaviors in amorphous alloys.This study focuses on Pd_(82)Si_(18)as the research object to further elucidate the underlying mechanism of caged dynamics from multiple perspectives,including the cage's lifetime,atomic local environment,and atomic potential energy.The results reveal that Si atoms exhibit a pronounced cage effect due to the hindrance of Pd atoms,resulting in an anomalous peak in the non-Gaussian parameters.An in-depth investigation was conducted on the caged dynamics differences between fast and slow Si atoms.In comparison to fast Si atoms,slow Si atoms were surrounded by more Pd atoms and occupied lower potential energy states,resulting in smaller diffusion displacements for the slow Si atoms.Concurrently,slow Si atoms tend to be in the centers of smaller clusters with coordination numbers of 9 and 10.During the isothermal relaxation process,clusters with coordination numbers 9 and 10 have longer lifetimes,suggesting that the escape of slow Si atoms from their cages is more challenging.The findings mentioned above hold significant implications for understanding the caged dynamics.展开更多
Mg86.33Ni13.67-xYx(x=0, 1, 3, 6, 10) amorphous alloys were obtained by single-roller melt-spinning technique and the effect of Y addition on the glass forming ability(GFA), crystallization and micro-hardness of Mg-Ni ...Mg86.33Ni13.67-xYx(x=0, 1, 3, 6, 10) amorphous alloys were obtained by single-roller melt-spinning technique and the effect of Y addition on the glass forming ability(GFA), crystallization and micro-hardness of Mg-Ni alloys were studied. The results show that the GFA of Mg86.33Ni13.67-xYx(x=0, 1, 3, 6, 10) is improved successfully with the Y addition. The highest GFA appeares at x=6, while the reduced glass transition temperature (Trg) is 0.5225 and the supercooled liquid region(ΔTx) is 42.06 K; the position of the main diffraction halo is different for the alloys, and the maximum of the main diffraction halo of alloys with x=0, 1, 3 corresponds to the main peaks of a metastable fcc-Mg6Ni or fcc-Mg6Ni + Ni-Y intermetallic phases, and for the alloys with x=6, 10, it corresponds to Mg-Y and Ni-Y intermetallic phases; the micro-hardness of the alloys is improved with Y additions, and the highest micro-hardness is obtained at x=6 at.%, which is 960 MPa.展开更多
Ni-W alloys and their composite deposits are electroplated on the metals when an appropriate complex agent is selected on the base of the theories of electrochemistry and complex chemistry, and the principle of induce...Ni-W alloys and their composite deposits are electroplated on the metals when an appropriate complex agent is selected on the base of the theories of electrochemistry and complex chemistry, and the principle of induced codeposition. Effects of the bath composition, pH value, temperature and current density on the electrode position of Ni-W alloys and their composite deposits have been investigated, and the effect of heat treatment temperature on the hardness, structure and cohesive force of the amorphous Ni-W alloys and their composite deposits are also discussed. Results showed that the alloys containing more than 44 wt pct W content and the composite deposits containing 7.8 wt pct SiC content could be obtained by making use of the appropriate bath composition and plating conditions. Alloys and their composite deposits with over 44 wt pct W content show amorphous structure. The hardness of amorphous Ni-W alloys and their composite deposits increases obviously when heated, and can reach to 1350 HV and 1520 HV respectively for 46 wt pct W content. The cohesion on Cu, carbon steel and stainless steel is very good.展开更多
The effects of Nd addition on corrosion behavior of Mg66Zn30Ca4 amorphous alloys in simulated body f luids(SBF) were studied in this paper. Electrochemical properties of the samples before and after corrosion were det...The effects of Nd addition on corrosion behavior of Mg66Zn30Ca4 amorphous alloys in simulated body f luids(SBF) were studied in this paper. Electrochemical properties of the samples before and after corrosion were determined. Surface morphologies of samples after immersion in SBF at 37℃ for different times were observed under scanning electron microscope(SEM). Results show that the corrosion resistance of Mg-based alloys in SBF is improved with the addition of Nd element. The electrochemical properties indicate that microalloying Nd element to the alloys leads to an ennoblement in the open circuit potentials of the alloys and a decrease in the anodic current density in SBF, especially for the Mg66-xZn30Ca4 Ndx alloys with Nd content of 1.0at.%-1.5at.%. It was observed that the surface morphologies of the alloys immersed in SBF change with the Nd addition. A f lakelike structure parallel to the alloy substrate formed on the surface of 1.0at.% Nd-containing alloy immersed in SBF for 7 days improves the corrosion resistance of the amorphous alloys by blocking the corrosion liquid from attacking the alloys.展开更多
A small amount of Ni was added into the binary Gd50Co50 amorphous alloy to replace Gd in order to obtain ternary Co50Gd50-xNx(x=1,2,and 3)amorphous alloys.Compared to the binary Gd50Co50 amorphous alloy,the Co50Gd50-x...A small amount of Ni was added into the binary Gd50Co50 amorphous alloy to replace Gd in order to obtain ternary Co50Gd50-xNx(x=1,2,and 3)amorphous alloys.Compared to the binary Gd50Co50 amorphous alloy,the Co50Gd50-xNx amorphous alloys show an enhanced Curie temperature(TC)with a weakened formability.The maximum magnetic entropy change(-Δ^Smpeak)of the Co50Gd50-xNx amorphous alloys is found to decrease with the increasing TC.The adiabatic temperature rise(ΔTad)of the Co50Gd47Ni3 amorphous alloy is superior to that of the Fe-based metallic glasses at room temperature.The variation of the TC and-Δ^Smpeak of the Gd50Co50 amorphous alloy with Ni addition,and the mechanism involved,were discussed.展开更多
Annealing at Ta=200℃ or so, the enhancement in the average tensile fracture strength of as-quenched (Fe0.99Mo0.01)78Si9B13 metallic glass increases about 7～8%. The origin of the annealing embrittlement at 244℃ in t...Annealing at Ta=200℃ or so, the enhancement in the average tensile fracture strength of as-quenched (Fe0.99Mo0.01)78Si9B13 metallic glass increases about 7～8%. The origin of the annealing embrittlement at 244℃ in the metallic glass (Fe0.99 Mo0.01)78Si9B13 was revealed that due to the formation of nanoscale granular with bcc structure resulting in the stress localization.The temperature of annealing embrittlement was in agreement with the calculated value from Tbcc=0.637Tc (Tc is the crystallized temperature), based on micromechanism of crystallization of metallic glass.展开更多
A new type of lightweight AlNiLa medium entropy amorphous alloy composite ribbons(labled as MEAAC ribbons)were prepared by vacuum arc melting technology and high-speed single roller meltspinning method.The microstruct...A new type of lightweight AlNiLa medium entropy amorphous alloy composite ribbons(labled as MEAAC ribbons)were prepared by vacuum arc melting technology and high-speed single roller meltspinning method.The microstructure and thermal stability of MEAAC ribbons were examined using X-ray diffraction,differential scanning calorimeter,and scanning electron microscope.Meanwhile,the hardness and surface roughness of these ribbons were measured by Vickers microhardness tester and atomic force microscope.The potentiodynamic polarization curves and electrochemical impedance spectroscopy(EIS)were applied to investigate the corrosion behavior of these MEAAC ribbons in simulated seawater(3.5wt%NaCl corrosive solution)at room temperature.The results demonstrate that AlNiLa MEAAC ribbons in the as-received state are mainly composed of amorphous phase and intermetallic compounds.The hardness values of all melt-spun ribbons are above 310 HV_(0.1).With the increase of Al content,the linear polarization resistances of four various AlNiLa MEAAC ribbons are negligibly different numerically.It is also found that Al_(45)Ni_(27.5)La_(27.5) MEAAC ribbons have the most positive corrosion potential and the smallest corrosion current density at the same time;hence it may be a kind of potential material for metal surface protection in harsh ocean environment.展开更多
The structural and magnetic properties of Fe_(80)P_9B_(11) amorphous alloy are investigated through ab initio molecular dynamic simulation. The structure evolution of Fe_(80)P_9B_(11) amorphous alloy can be described ...The structural and magnetic properties of Fe_(80)P_9B_(11) amorphous alloy are investigated through ab initio molecular dynamic simulation. The structure evolution of Fe_(80)P_9B_(11) amorphous alloy can be described in the framework of topological fluctuation theory, and the fluctuation of atomic hydrostatic stress gradually decreases upon cooling. The left sub peak of the second peak of Fe–B partial pair distribution functions(PDFs) becomes pronounced below the glass transition temperature, which may be the major reason why B promotes the glass formation ability significantly. The magnetization mainly originates from Fe 3d states, while small contribution results from metalloid elements P and B. This work may be helpful for developing Fe-based metallic glasses with both high saturation flux density and glass formation ability.展开更多
The addition of early transition metals(ETMs) into Fe-based amorphous alloys is practically found to be effective in reducing the α-Fe grain size in crystallization process. In this paper, by using ab initio molecula...The addition of early transition metals(ETMs) into Fe-based amorphous alloys is practically found to be effective in reducing the α-Fe grain size in crystallization process. In this paper, by using ab initio molecular dynamics simulations, the mechanism of the effect of two typical ETMs(Nb and W) on nano-crystallization is studied. It is found that the diffusion ability in amorphous alloy is mainly determined by the bonding energy of the atom rather than the size or weight of the atom. The alloying of B dramatically reduces the diffusion ability of the ETM atoms, which prevents the supply of Fe near the grain surface and consequently suppresses the growth of α-Fe grains. Moreover, the difference in grain refining effectiveness between Nb and W could be attributed to the larger bonding energy between Nb and B than that between W and B.展开更多
Amorphous alloy(MGs)is a solid alloy with disordered atomic accumulation obtained by ultra-rapid solidification of alloy melt.The atom deviates from the equilibrium position and is in metastable state.Up to now,a larg...Amorphous alloy(MGs)is a solid alloy with disordered atomic accumulation obtained by ultra-rapid solidification of alloy melt.The atom deviates from the equilibrium position and is in metastable state.Up to now,a large number of MGs have been applied to the treatment of dye and heavy metal contaminated wastewater and ideal experimental results have been obtained.However,there is no literature to systematically summarize the chemical reaction and degradation mechanism in the process of degradation.On the basis of reviewing the classification,application,and synthesis of MGs,this paper introduces in detail the chemical reactions such as decolorization,mineralization,and ion leaching of Fe-based amorphous alloy(Fe-MGs)in the degradation of organic and inorganic salt wastewater through direct reduction or advanced oxidation mechanism.Compared with crystalline materials,the higher reaction rate of Fe-MGs can be attributed to lower activation energy,negative redox potential,loose product layer,and band structure with downward shift of valence band top.Finally,some suggestions and prospects are put forward for the limitations and research prospects of MGs in the environmental field,which provides a new idea for the synthesis of new environmental functional materials.展开更多
L1_(0)-FeNi hard magnetic alloy with coercivity reaching 861 Oe was synthesized through annealing Fe_(42)Ni_(41.3)Si_8 B_(4)P_(4)Cu_(0.7)amorphous alloy,and the L1_(0)-FeNi formation mechanism has been studied.It is f...L1_(0)-FeNi hard magnetic alloy with coercivity reaching 861 Oe was synthesized through annealing Fe_(42)Ni_(41.3)Si_8 B_(4)P_(4)Cu_(0.7)amorphous alloy,and the L1_(0)-FeNi formation mechanism has been studied.It is found the L1_(0)-FeNi in annealed samples at 400℃mainly originated from the residual amorphous phase during the second stage of crystallization which could take place over 600 C lower than the measured onset temperature of the second stage with a50 C/min heating rate.Annealing at 4000 C after fully crystallization still caused a slight increase of coercivity,which was probably contributed by the limited transformation from other high temperature crystalline phases towards L1_(0)phase,or the removal of B from L1_(0)lattice and improvement of the ordering quality of L1_(0)phase due to the reduced temperature from520℃to 400℃.The first stage of crystallization has hardly direct contribution to L1_(0)-FeNi formation.Ab initio simulations show that the addition of Si or Co in L1_(0)-FeNi has the effect of enhancing the thermal stability of L1_(0)phase without seriously deteriorating its magnetic hardness.The non-monotonic feature of direction dependent coercivity in ribbon segments resulted from the combination of domain wall pinning and demagnetization effects.The approaches of synthesizing L1_(0)-FeNi magnets by adding Si or Co and decreasing the onset crystallization temperature have been discussed in detail.展开更多
The behaviour of hydrogen permeation and diffusion in amorphous alloy Ni68Cr7Si8B14Fe3 hasbeen investigated by an ultrahigh vacuum gas permeation technique. A comparison experimentwas carried out between the as-quench...The behaviour of hydrogen permeation and diffusion in amorphous alloy Ni68Cr7Si8B14Fe3 hasbeen investigated by an ultrahigh vacuum gas permeation technique. A comparison experimentwas carried out between the as-quenched and annealed States (400℃/2h) of the amorphousalloy. The results show that, for both states of the amorphous alloy in the temperature rangeof 200～350℃, the diffusivity and permeability of hydrogen are in agreement with Arrheniusrelationship, there does not exist H-trapping effect, and the activation energies of diffusion andpermeation almost keep the same.展开更多
Many amorphous alloys have been developed to date,but the low plasticity has limited their application.To achieve an amorphous alloy with high plasticity,a series of(Ti_(40)Zr_(25)Cu_(9)Ni_(8) Be_(18))_(100-x)TM_(x)(x...Many amorphous alloys have been developed to date,but the low plasticity has limited their application.To achieve an amorphous alloy with high plasticity,a series of(Ti_(40)Zr_(25)Cu_(9)Ni_(8) Be_(18))_(100-x)TM_(x)(x=0,1,2,3,4 at.%,TM=Nb,Y)alloys were designed to study the influence of Nb and Y addition on the plasticity.The amorphous samples were prepared using the vacuum melting and copper mold casting process.The microstructures,glass forming ability and mechanical properties of the alloys were investigated by X-ray diffractometry(XRD),scanning electron microscopy(SEM),high-resolution transmission electron microscopy(HRTEM),depth-sensitive nanoindentation,and uniaxial compressive test.The plasticity of different bulk amorphous alloys was investigated by measuring the plastic deformation energy(PDE)during loading.The relationship between the PDE value and plasticity in bulk amorphous alloys was explored.Results show that Nb addition decreases the PDE value and promotes the generation of multiple shear bands,which significantly increases the fracture strength and plasticity,while the addition of Y element reduces the fracture strength and plastic strain of the alloy.展开更多
A ferromagnetic amorphous Fe73Al4Ge2Nb1 P10C6B4 alloy with high glass-forming ability was synthesized by melt spinning. The supercooled liquid region before crystallization reaches about 65.7 K. The crystallized struc...A ferromagnetic amorphous Fe73Al4Ge2Nb1 P10C6B4 alloy with high glass-forming ability was synthesized by melt spinning. The supercooled liquid region before crystallization reaches about 65.7 K. The crystallized structure consists of a-Fe, Fe3B, FeB, Fe3P and Fe3C phases. The Febased amorphous alloy exhibits good magnetic properties With a high saturation magnetization and a low saturated magnetostriction. The crystallization leads to an obvious decrease in the soft magnetic properties.展开更多
Because of its unique long range disordered structure and numerous free volume,amorphous alloy is considered to be able to accommodate the damage caused by ion bombardment and has good irradiation resistance.2 MeV He+...Because of its unique long range disordered structure and numerous free volume,amorphous alloy is considered to be able to accommodate the damage caused by ion bombardment and has good irradiation resistance.2 MeV He+ions were selected to irradiate amorphous alloy Fe80Si7B13,and it was found that the arrangement of atoms in the amorphous alloy became uneven.In the bubble layer located near the He ion range which was about 3.5μm from the surface,the local atoms had a tendency of ordered arrangement.Under the irradiation,no obvious damage could be observed on the surface of the amorphous alloy,while the surface roughness increased,which reduced the surface relative reflectivity of the amorphous alloy.After the irradiation,the Fe-based amorphous alloy maintained the soft magnetic performance.The variation of atomic arrangement in the amorphous alloy enhanced its saturation magnetic induction intensity.展开更多
To make a kind of magnetic field caused by the strip-wound cut cores made from amorphous alloy,it can be used for the maker of magnetic distilled water with the function of magnetic cure and health protection.
Mg-based amorphous alloys exhibit efficient catalytic performance and excellent biocompatibility with a promising application probability,specifically in the field of azo dye wastewater degradation.However,the problem...Mg-based amorphous alloys exhibit efficient catalytic performance and excellent biocompatibility with a promising application probability,specifically in the field of azo dye wastewater degradation.However,the problems like difficulty in preparation and poor cycling stability need to be solved.At present,Mg-based amorphous alloys applied in wastewater degradation are available in powder and ribbon.The amorphous alloy powder fabricated by ball milling has a high specific surface area,and its reactivity is thousands of times better than that of gas atomized alloy powder.But the development is limited due to the high energy consumption,difficult and costly process of powder recycling.The single roller melt-spinning method is a new manufacturing process of amorphous alloy ribbon.Compared to amorphous powder,the specific surface area of amorphous ribbon is relatively lower,therefore,it is necessary to carry out surface modification to enhance it.Dealloying is a way that can form a pore structure on the surface of the amorphous alloys,increasing the specific surface area and providing more reactive sites,which all contribute to the catalytic performance.Exploring the optimal conditions for Mg-based amorphous alloys in wastewater degradation by adjusting amorphous alloy composition,choosing suitable method to preparation and surface modification,reducing cost,expanding the pH range will advance the steps to put Mg-based amorphous alloys in industrial environments into practice.展开更多
Amorphous alloys,also known as metallic glasses,are solid metallic materials having long-range disordered atomic structures.Compared to crystalline alloys,amorphous alloys not only have metallic characters,but also po...Amorphous alloys,also known as metallic glasses,are solid metallic materials having long-range disordered atomic structures.Compared to crystalline alloys,amorphous alloys not only have metallic characters,but also possess several distinct properties associated to the amorphous structure,such as isotropy,composition flexibility,unsaturated surface,etc.As a result,amorphous alloys offer a class of highly promising materials for catalyzing electrochemical reactions.In this minireview,the preparation,characterization and electrocatalytic performances of a variety of metallic amorphous alloy materials are summarized.The influences of the amorphous alloy structure on different electrochemical reactions are discussed.Finally,a summary on the advantages and challenges of amorphous alloys in electrocatalysis is provided,along with some perspectives about the future research directions.展开更多
A new Al-based amorphous alloy with excellent corrosion resistance and high thermal stability was produced in the Al-Co-RE(Ce-La)system.In this regard,two different amorphous-nanocrystalline ribbons:Al_(87.6)-Co_(6.4)...A new Al-based amorphous alloy with excellent corrosion resistance and high thermal stability was produced in the Al-Co-RE(Ce-La)system.In this regard,two different amorphous-nanocrystalline ribbons:Al_(87.6)-Co_(6.4)-Ce_(3.8-)La_(2.2)(M_(1))and Al_(82.3)-Co_(10.1)-Ce_(4.8)-La_(2.8)(M_(2))were prepared using melt spinning.The results reveal the supercooled liquid region(ATx)of 218℃which shows that the M2alloy has higher thermal stability in comparison to the M1alloy.The M2ribbons present the superior corrosion resistance because of the formation of amorphous phase.The icorr,Ecorr,Epit,and Epit-Ecorrvalues of fully amorphous Al-Co-Ce-La metallic ribbons have a better trend of anti-corrosion performance compared to other crystalline and amorphous aluminum alloys.展开更多
A crucial step in creating cutting-edge soft magnetic alloys is the nanocrystallization of Fe-based amorphous alloys.However,it is unclear how the thermal history affects the nanocrystallization.In this work,high-prec...A crucial step in creating cutting-edge soft magnetic alloys is the nanocrystallization of Fe-based amorphous alloys.However,it is unclear how the thermal history affects the nanocrystallization.In this work,high-precision nanocalorimetry and in-situ hightemperature transmission electron microscopy are used to systematically examine how the pre-annealing relaxation process affects the nanocrystallization of Fe-based amorphous alloys.We discover that the glass with more thermal energy storage will crystallize into superb nanocrystalline structures with exceptionally advanced soft magnetism.The soft magnetic properties of Fe-B nanocrystalline alloys can be improved by increasing the relaxation temperature.This finding provides solid and clear evidence for the influences of thermal history on crystallization behavior for Fe-based amorphous alloys,which is helpful for designing advanced soft magnetic nanocrystalline alloys.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No.51701071)the Natural Science Foundation of Hunan Province,China (Grant Nos.2022JJ50115 and 2021JJ30179)the Research Foundation of the Education Bureau of Hunan Province,China (Grant No.22A0522)。
文摘To date,there is still a lack of a comprehensive explanation for caged dynamics which is regarded as one of the intricate dynamic behaviors in amorphous alloys.This study focuses on Pd_(82)Si_(18)as the research object to further elucidate the underlying mechanism of caged dynamics from multiple perspectives,including the cage's lifetime,atomic local environment,and atomic potential energy.The results reveal that Si atoms exhibit a pronounced cage effect due to the hindrance of Pd atoms,resulting in an anomalous peak in the non-Gaussian parameters.An in-depth investigation was conducted on the caged dynamics differences between fast and slow Si atoms.In comparison to fast Si atoms,slow Si atoms were surrounded by more Pd atoms and occupied lower potential energy states,resulting in smaller diffusion displacements for the slow Si atoms.Concurrently,slow Si atoms tend to be in the centers of smaller clusters with coordination numbers of 9 and 10.During the isothermal relaxation process,clusters with coordination numbers 9 and 10 have longer lifetimes,suggesting that the escape of slow Si atoms from their cages is more challenging.The findings mentioned above hold significant implications for understanding the caged dynamics.
基金supported by the Award Fund for Outstanding Young Scientist in Shandong Province, China (No. BS2011CL004)
文摘Mg86.33Ni13.67-xYx(x=0, 1, 3, 6, 10) amorphous alloys were obtained by single-roller melt-spinning technique and the effect of Y addition on the glass forming ability(GFA), crystallization and micro-hardness of Mg-Ni alloys were studied. The results show that the GFA of Mg86.33Ni13.67-xYx(x=0, 1, 3, 6, 10) is improved successfully with the Y addition. The highest GFA appeares at x=6, while the reduced glass transition temperature (Trg) is 0.5225 and the supercooled liquid region(ΔTx) is 42.06 K; the position of the main diffraction halo is different for the alloys, and the maximum of the main diffraction halo of alloys with x=0, 1, 3 corresponds to the main peaks of a metastable fcc-Mg6Ni or fcc-Mg6Ni + Ni-Y intermetallic phases, and for the alloys with x=6, 10, it corresponds to Mg-Y and Ni-Y intermetallic phases; the micro-hardness of the alloys is improved with Y additions, and the highest micro-hardness is obtained at x=6 at.%, which is 960 MPa.
文摘Ni-W alloys and their composite deposits are electroplated on the metals when an appropriate complex agent is selected on the base of the theories of electrochemistry and complex chemistry, and the principle of induced codeposition. Effects of the bath composition, pH value, temperature and current density on the electrode position of Ni-W alloys and their composite deposits have been investigated, and the effect of heat treatment temperature on the hardness, structure and cohesive force of the amorphous Ni-W alloys and their composite deposits are also discussed. Results showed that the alloys containing more than 44 wt pct W content and the composite deposits containing 7.8 wt pct SiC content could be obtained by making use of the appropriate bath composition and plating conditions. Alloys and their composite deposits with over 44 wt pct W content show amorphous structure. The hardness of amorphous Ni-W alloys and their composite deposits increases obviously when heated, and can reach to 1350 HV and 1520 HV respectively for 46 wt pct W content. The cohesion on Cu, carbon steel and stainless steel is very good.
基金financially supported by the"100 Talents Project"of Hebei Province,China(E2012100009)the Key Research Items in Science and Technology Support Program of Tianjin,China(12ZCZDGX46100)+1 种基金the Natural Science Foundation of Hebei Province,China(E2012202017)the National High Technology Research and Development Program(863 Program)of China(2013AA031002)
文摘The effects of Nd addition on corrosion behavior of Mg66Zn30Ca4 amorphous alloys in simulated body f luids(SBF) were studied in this paper. Electrochemical properties of the samples before and after corrosion were determined. Surface morphologies of samples after immersion in SBF at 37℃ for different times were observed under scanning electron microscope(SEM). Results show that the corrosion resistance of Mg-based alloys in SBF is improved with the addition of Nd element. The electrochemical properties indicate that microalloying Nd element to the alloys leads to an ennoblement in the open circuit potentials of the alloys and a decrease in the anodic current density in SBF, especially for the Mg66-xZn30Ca4 Ndx alloys with Nd content of 1.0at.%-1.5at.%. It was observed that the surface morphologies of the alloys immersed in SBF change with the Nd addition. A f lakelike structure parallel to the alloy substrate formed on the surface of 1.0at.% Nd-containing alloy immersed in SBF for 7 days improves the corrosion resistance of the amorphous alloys by blocking the corrosion liquid from attacking the alloys.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51671119 and 51871139)the Chongqing Research Program of Basic Research and Frontier Technology,China(Grant No.cstc2018jcyjAX0329 and cstc2018jcyjAX0444)the Key Project of Science and Technology Research Program of Chongqing Education Commission of China(Grant No.KJZD-K201900501).
文摘A small amount of Ni was added into the binary Gd50Co50 amorphous alloy to replace Gd in order to obtain ternary Co50Gd50-xNx(x=1,2,and 3)amorphous alloys.Compared to the binary Gd50Co50 amorphous alloy,the Co50Gd50-xNx amorphous alloys show an enhanced Curie temperature(TC)with a weakened formability.The maximum magnetic entropy change(-Δ^Smpeak)of the Co50Gd50-xNx amorphous alloys is found to decrease with the increasing TC.The adiabatic temperature rise(ΔTad)of the Co50Gd47Ni3 amorphous alloy is superior to that of the Fe-based metallic glasses at room temperature.The variation of the TC and-Δ^Smpeak of the Gd50Co50 amorphous alloy with Ni addition,and the mechanism involved,were discussed.
文摘Annealing at Ta=200℃ or so, the enhancement in the average tensile fracture strength of as-quenched (Fe0.99Mo0.01)78Si9B13 metallic glass increases about 7～8%. The origin of the annealing embrittlement at 244℃ in the metallic glass (Fe0.99 Mo0.01)78Si9B13 was revealed that due to the formation of nanoscale granular with bcc structure resulting in the stress localization.The temperature of annealing embrittlement was in agreement with the calculated value from Tbcc=0.637Tc (Tc is the crystallized temperature), based on micromechanism of crystallization of metallic glass.
基金by the National Key R&D Program of China(No.2018YFC1902400)the National Natural Science Foundation of China(No.51975582)the Natural Science Foundation of Beijing,China(No.2212055)。
文摘A new type of lightweight AlNiLa medium entropy amorphous alloy composite ribbons(labled as MEAAC ribbons)were prepared by vacuum arc melting technology and high-speed single roller meltspinning method.The microstructure and thermal stability of MEAAC ribbons were examined using X-ray diffraction,differential scanning calorimeter,and scanning electron microscope.Meanwhile,the hardness and surface roughness of these ribbons were measured by Vickers microhardness tester and atomic force microscope.The potentiodynamic polarization curves and electrochemical impedance spectroscopy(EIS)were applied to investigate the corrosion behavior of these MEAAC ribbons in simulated seawater(3.5wt%NaCl corrosive solution)at room temperature.The results demonstrate that AlNiLa MEAAC ribbons in the as-received state are mainly composed of amorphous phase and intermetallic compounds.The hardness values of all melt-spun ribbons are above 310 HV_(0.1).With the increase of Al content,the linear polarization resistances of four various AlNiLa MEAAC ribbons are negligibly different numerically.It is also found that Al_(45)Ni_(27.5)La_(27.5) MEAAC ribbons have the most positive corrosion potential and the smallest corrosion current density at the same time;hence it may be a kind of potential material for metal surface protection in harsh ocean environment.
基金supported by the National Natural Science Foundation of China(Grant No.51571115)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘The structural and magnetic properties of Fe_(80)P_9B_(11) amorphous alloy are investigated through ab initio molecular dynamic simulation. The structure evolution of Fe_(80)P_9B_(11) amorphous alloy can be described in the framework of topological fluctuation theory, and the fluctuation of atomic hydrostatic stress gradually decreases upon cooling. The left sub peak of the second peak of Fe–B partial pair distribution functions(PDFs) becomes pronounced below the glass transition temperature, which may be the major reason why B promotes the glass formation ability significantly. The magnetization mainly originates from Fe 3d states, while small contribution results from metalloid elements P and B. This work may be helpful for developing Fe-based metallic glasses with both high saturation flux density and glass formation ability.
基金Project supported by the National Key Research and Development Program of China(Grant No.2016YFB0300502)the Shenzhen Municipal Fundamental Science and Technology Research Program,China(Grant No.JCYJ20170815162201821)the Fundamental Research Funds for Central Universities,China(Grant No.31020170QD102)
文摘The addition of early transition metals(ETMs) into Fe-based amorphous alloys is practically found to be effective in reducing the α-Fe grain size in crystallization process. In this paper, by using ab initio molecular dynamics simulations, the mechanism of the effect of two typical ETMs(Nb and W) on nano-crystallization is studied. It is found that the diffusion ability in amorphous alloy is mainly determined by the bonding energy of the atom rather than the size or weight of the atom. The alloying of B dramatically reduces the diffusion ability of the ETM atoms, which prevents the supply of Fe near the grain surface and consequently suppresses the growth of α-Fe grains. Moreover, the difference in grain refining effectiveness between Nb and W could be attributed to the larger bonding energy between Nb and B than that between W and B.
基金This research was funded by the National Natural Science Foundation of China(NSFC)[Grant Nos.51661015 and 52061024]the Natural Science Foundation of Zhejiang Province[Grant No.LQ20E010002].
文摘Amorphous alloy(MGs)is a solid alloy with disordered atomic accumulation obtained by ultra-rapid solidification of alloy melt.The atom deviates from the equilibrium position and is in metastable state.Up to now,a large number of MGs have been applied to the treatment of dye and heavy metal contaminated wastewater and ideal experimental results have been obtained.However,there is no literature to systematically summarize the chemical reaction and degradation mechanism in the process of degradation.On the basis of reviewing the classification,application,and synthesis of MGs,this paper introduces in detail the chemical reactions such as decolorization,mineralization,and ion leaching of Fe-based amorphous alloy(Fe-MGs)in the degradation of organic and inorganic salt wastewater through direct reduction or advanced oxidation mechanism.Compared with crystalline materials,the higher reaction rate of Fe-MGs can be attributed to lower activation energy,negative redox potential,loose product layer,and band structure with downward shift of valence band top.Finally,some suggestions and prospects are put forward for the limitations and research prospects of MGs in the environmental field,which provides a new idea for the synthesis of new environmental functional materials.
基金supported by the National Natural Science Foundation of China(Grant Nos.51971179 and 51971180)the Natural Science Foundation of Chongqing,China(Grant No.cstc2019jcyj-msxmX0328)+3 种基金Shaanxi Provincial Natural Science Foundation,China(Grant No.2020JM-112)Guangdong Provincial Science and Technology Program,China(Grant No.2019B090905009)the Fundamental Research Funds for the Central Universities of China(Grant No.D5000210731)Shaanxi Provincial Key R&D Program,China(Grant No.2021KWZ-13)。
文摘L1_(0)-FeNi hard magnetic alloy with coercivity reaching 861 Oe was synthesized through annealing Fe_(42)Ni_(41.3)Si_8 B_(4)P_(4)Cu_(0.7)amorphous alloy,and the L1_(0)-FeNi formation mechanism has been studied.It is found the L1_(0)-FeNi in annealed samples at 400℃mainly originated from the residual amorphous phase during the second stage of crystallization which could take place over 600 C lower than the measured onset temperature of the second stage with a50 C/min heating rate.Annealing at 4000 C after fully crystallization still caused a slight increase of coercivity,which was probably contributed by the limited transformation from other high temperature crystalline phases towards L1_(0)phase,or the removal of B from L1_(0)lattice and improvement of the ordering quality of L1_(0)phase due to the reduced temperature from520℃to 400℃.The first stage of crystallization has hardly direct contribution to L1_(0)-FeNi formation.Ab initio simulations show that the addition of Si or Co in L1_(0)-FeNi has the effect of enhancing the thermal stability of L1_(0)phase without seriously deteriorating its magnetic hardness.The non-monotonic feature of direction dependent coercivity in ribbon segments resulted from the combination of domain wall pinning and demagnetization effects.The approaches of synthesizing L1_(0)-FeNi magnets by adding Si or Co and decreasing the onset crystallization temperature have been discussed in detail.
文摘The behaviour of hydrogen permeation and diffusion in amorphous alloy Ni68Cr7Si8B14Fe3 hasbeen investigated by an ultrahigh vacuum gas permeation technique. A comparison experimentwas carried out between the as-quenched and annealed States (400℃/2h) of the amorphousalloy. The results show that, for both states of the amorphous alloy in the temperature rangeof 200～350℃, the diffusivity and permeability of hydrogen are in agreement with Arrheniusrelationship, there does not exist H-trapping effect, and the activation energies of diffusion andpermeation almost keep the same.
基金supported by the National Natural Science Foundation of China(Grant Nos.:51434008,51671166,51471143)。
文摘Many amorphous alloys have been developed to date,but the low plasticity has limited their application.To achieve an amorphous alloy with high plasticity,a series of(Ti_(40)Zr_(25)Cu_(9)Ni_(8) Be_(18))_(100-x)TM_(x)(x=0,1,2,3,4 at.%,TM=Nb,Y)alloys were designed to study the influence of Nb and Y addition on the plasticity.The amorphous samples were prepared using the vacuum melting and copper mold casting process.The microstructures,glass forming ability and mechanical properties of the alloys were investigated by X-ray diffractometry(XRD),scanning electron microscopy(SEM),high-resolution transmission electron microscopy(HRTEM),depth-sensitive nanoindentation,and uniaxial compressive test.The plasticity of different bulk amorphous alloys was investigated by measuring the plastic deformation energy(PDE)during loading.The relationship between the PDE value and plasticity in bulk amorphous alloys was explored.Results show that Nb addition decreases the PDE value and promotes the generation of multiple shear bands,which significantly increases the fracture strength and plasticity,while the addition of Y element reduces the fracture strength and plastic strain of the alloy.
文摘A ferromagnetic amorphous Fe73Al4Ge2Nb1 P10C6B4 alloy with high glass-forming ability was synthesized by melt spinning. The supercooled liquid region before crystallization reaches about 65.7 K. The crystallized structure consists of a-Fe, Fe3B, FeB, Fe3P and Fe3C phases. The Febased amorphous alloy exhibits good magnetic properties With a high saturation magnetization and a low saturated magnetostriction. The crystallization leads to an obvious decrease in the soft magnetic properties.
基金by National Natural Science Foundation of China(Nos.11675035,11975065 and 11375037).
文摘Because of its unique long range disordered structure and numerous free volume,amorphous alloy is considered to be able to accommodate the damage caused by ion bombardment and has good irradiation resistance.2 MeV He+ions were selected to irradiate amorphous alloy Fe80Si7B13,and it was found that the arrangement of atoms in the amorphous alloy became uneven.In the bubble layer located near the He ion range which was about 3.5μm from the surface,the local atoms had a tendency of ordered arrangement.Under the irradiation,no obvious damage could be observed on the surface of the amorphous alloy,while the surface roughness increased,which reduced the surface relative reflectivity of the amorphous alloy.After the irradiation,the Fe-based amorphous alloy maintained the soft magnetic performance.The variation of atomic arrangement in the amorphous alloy enhanced its saturation magnetic induction intensity.
文摘To make a kind of magnetic field caused by the strip-wound cut cores made from amorphous alloy,it can be used for the maker of magnetic distilled water with the function of magnetic cure and health protection.
基金supported by the National Natural Science Foundation of China(Grant No.52071276)the Natural Science Foundation of Chongqing,China(Grant No.CSTB2022NSCQ-MSX0440)the Fundamental Research Funds for the Central Universities(Grant No.SWUXDJH202313,SWU-KQ22083).
文摘Mg-based amorphous alloys exhibit efficient catalytic performance and excellent biocompatibility with a promising application probability,specifically in the field of azo dye wastewater degradation.However,the problems like difficulty in preparation and poor cycling stability need to be solved.At present,Mg-based amorphous alloys applied in wastewater degradation are available in powder and ribbon.The amorphous alloy powder fabricated by ball milling has a high specific surface area,and its reactivity is thousands of times better than that of gas atomized alloy powder.But the development is limited due to the high energy consumption,difficult and costly process of powder recycling.The single roller melt-spinning method is a new manufacturing process of amorphous alloy ribbon.Compared to amorphous powder,the specific surface area of amorphous ribbon is relatively lower,therefore,it is necessary to carry out surface modification to enhance it.Dealloying is a way that can form a pore structure on the surface of the amorphous alloys,increasing the specific surface area and providing more reactive sites,which all contribute to the catalytic performance.Exploring the optimal conditions for Mg-based amorphous alloys in wastewater degradation by adjusting amorphous alloy composition,choosing suitable method to preparation and surface modification,reducing cost,expanding the pH range will advance the steps to put Mg-based amorphous alloys in industrial environments into practice.
基金supported by the Ministry of Education of Singapore under Tier 1 RG115/18 and RG4/20,and Tier 2 T2EP10120-0009.
文摘Amorphous alloys,also known as metallic glasses,are solid metallic materials having long-range disordered atomic structures.Compared to crystalline alloys,amorphous alloys not only have metallic characters,but also possess several distinct properties associated to the amorphous structure,such as isotropy,composition flexibility,unsaturated surface,etc.As a result,amorphous alloys offer a class of highly promising materials for catalyzing electrochemical reactions.In this minireview,the preparation,characterization and electrocatalytic performances of a variety of metallic amorphous alloy materials are summarized.The influences of the amorphous alloy structure on different electrochemical reactions are discussed.Finally,a summary on the advantages and challenges of amorphous alloys in electrocatalysis is provided,along with some perspectives about the future research directions.
文摘A new Al-based amorphous alloy with excellent corrosion resistance and high thermal stability was produced in the Al-Co-RE(Ce-La)system.In this regard,two different amorphous-nanocrystalline ribbons:Al_(87.6)-Co_(6.4)-Ce_(3.8-)La_(2.2)(M_(1))and Al_(82.3)-Co_(10.1)-Ce_(4.8)-La_(2.8)(M_(2))were prepared using melt spinning.The results reveal the supercooled liquid region(ATx)of 218℃which shows that the M2alloy has higher thermal stability in comparison to the M1alloy.The M2ribbons present the superior corrosion resistance because of the formation of amorphous phase.The icorr,Ecorr,Epit,and Epit-Ecorrvalues of fully amorphous Al-Co-Ce-La metallic ribbons have a better trend of anti-corrosion performance compared to other crystalline and amorphous aluminum alloys.
基金supported by the“Pioneer and Leading Goose”R&D Program of Zhejiang(Grant No.2022C01023)National Natural Science Foundation of China(Grant Nos.52101205,92163108,51922102,52001319,and 51971239)+1 种基金Hunan Key Laboratory of Design and Manufacture of Electromagnetic Equipment under the Open Foundation(Grant No.DC202005)Zhejiang Provincial Natural Science Foundation of China(Grant No.LGF22E010002).
文摘A crucial step in creating cutting-edge soft magnetic alloys is the nanocrystallization of Fe-based amorphous alloys.However,it is unclear how the thermal history affects the nanocrystallization.In this work,high-precision nanocalorimetry and in-situ hightemperature transmission electron microscopy are used to systematically examine how the pre-annealing relaxation process affects the nanocrystallization of Fe-based amorphous alloys.We discover that the glass with more thermal energy storage will crystallize into superb nanocrystalline structures with exceptionally advanced soft magnetism.The soft magnetic properties of Fe-B nanocrystalline alloys can be improved by increasing the relaxation temperature.This finding provides solid and clear evidence for the influences of thermal history on crystallization behavior for Fe-based amorphous alloys,which is helpful for designing advanced soft magnetic nanocrystalline alloys.
